Quantum frequency conversion of a quantum dot single-photon source on a nanophotonic chip

Abstract

Single self-assembled InAs/GaAs quantum dots are promising bright sources of indistinguishable photons for quantum information science. However, their distribution in emission wavelength, due to inhomogeneous broadening inherent to their growth, has limited the ability to create multiple identical sources. Quantum frequency conversion can overcome this issue, particularly if implemented using scalable chip-integrated technologies. Here, we report the first demonstration of quantum frequency conversion of a quantum dot single-photon source on a silicon nanophotonic chip. Single photons from a quantum dot in a micropillar cavity are shifted in wavelength with an on-chip conversion efficiency ≈ 12 %, limited by the linewidth of the quantum dot photons. The intensity autocorrelation function g (2) (τ ) for the frequency-converted light is antibunched with g (2) (0) = 0.290 ± 0.030, compared to the before-conversion value g (2) (0) = 0.080 ± 0.003. We demonstrate the suitability of our frequency conversion interface as a resource for quantum dot sources by characterizing its effectiveness across a wide span of input wavelengths (840 nm to 980 nm), and its ability to achieve tunable wavelength shifts difficult to obtain by other approaches.

Advanced Technologies for Quantum Photonic Devices Based on Epitaxial Quantum Dots

“…When replaced by single photons from QDs under p‐shell excitation, however, the conversion efficiency drops to ≈12%. This is because the QD emission has a bandwidth of around 2.9 GHz, which is larger than the 1.65 GHz bandwidth offered by the frequency converter …”

“…One limitation of such resonator‐based devices is that high conversion efficiencies can only be achieved when the signal bandwidth is sufficiently smaller than the conversion bandwidth, which is typically on the order of a few GHz. For example, a recent experimental study shows that the on‐chip conversion efficiency for a narrowband signal comprised of attenuated laser light is >30% with a total on‐chip pump power of 20 mW (see Figure b) . When replaced by single photons from QDs under p‐shell excitation, however, the conversion efficiency drops to ≈12%.…”

“…The power in the 930 nm band is normalized by the input signal power, corresponding to the on‐chip conversion efficiency for a narrowband input signal. Reproduced with permission . Copyright 2019, American Physical Society.…”

On-chip polarization rotator for type I second harmonic generation

“…Integrated versions of f -2f self-referencing are currently under development and are expected to open new applications for this technology [3][4][5] . Devices that produce efficient SHG are generally also suitable for efficient parametric down-conversion (PDC), an enabling process for integrated quantum photonic systems [6][7][8] .…”

Tunable Quantum Beat of Single Photons Enabled by Nonlinear Nanophotonics

“…1). The quantum source uses spontaneous four-wave mixing (SFWM) in a stoichiometric silicon nitride (Si 3 N 4 ) microring resonator to produce temporally-correlated photon pairs 4 , while quantum frequency conversion is implemented through four-wave mixing Bragg scattering (FWM-BS) 5 in a similar Si 3 N 4 microring 6,7 . The successful combination of photon pair generation and frequency conversion in a common platform enables frequency conversion of a quantum state of light and establishes its relevance to frequency-bin-encoded quantum photonics [1][2][3]8 .…”